A strategy of co-fermentation of distillers dried grains with solubles (DDGS) and lignocellulosic feedstocks as swine feed

Probiotic-Fermented Distillers Grain Alters the Rumen Microbiome, Metabolome, and Enzyme Activity, Enhancing the Immune Status of Finishing Cattle

A total of 30 Simmental crossbred cattle (6.50 months old, 265.0 ± 22.48 kg) were randomly divided into three groups, with 10 heads per group, and fed for 45 days. The diet treatments consisted of the Control group without PFDG supplementation, the PFDG-15% group with 15% PFDG substituting for 15% concentrate, and PFDG-30% group with 30% PFDG substituting for 30% concentrate. The results showed that compared with the Control group, the average daily gain (ADG) of the cattle in the PFDG-30% group decreased significantly (0.890 vs. 0.768 kg/d, p = 0.005). The serum malondialdehyde content of cattle in the PFDG-15% and PFDG-30% groups decreased significantly (p = 0.047) compared to that of the Control group. However, the serum superoxide dismutase activity of cattle in the PFDG-30% group was significantly higher than that of the Control group (p = 0.047). Meanwhile, both the PFDG-15% and PFDG-30% groups (1758.47 vs. 2061.30 μg/mL) showed higher serum levels of immunoglobulin G, while the interleukin-10 concentration was lower in the PFDG-30% group (p = 0.027). In addition, the PFDG-15% and PFDG-30% groups shifted the rumen microbiota by improving the abundances of F082 (related to propionic acid production) and fiber-degrading bacteria (Lachnospiraceae_UGG-009 and Prevotellaceae_UCG-001) and reducing the abundance of the disease-associated bacteria Selenomonas. A Kyoto encyclopedia of genes and genomes (KEGG) analysis illustrated that three key metabolic pathways, including phenylalanine metabolism, pyrimidine metabolism, and tryptophan metabolism, were enriched in the PFDG-15% group, but eight key metabolic pathways, including arachidonic acid metabolism, were enriched in the PFDG-30% group. Importantly, both the PFDG-15% and PFDG-30% groups increased (p < 0.01) the activities of cellulase, lipase, and protease in the rumen. Finally, the different bacterial abundance in the rumen was associated with changes in the ADG, serum antioxidant capacity, immune status, rumen enzyme activity, and metabolites. These results suggest that PFDG alters rumen microbiome abundance, metabolome, and enzyme activity for enhancing serum antioxidant capacity and the immune status, but when the supplemental level reaches 30%, it has a negative effect on ADG and the anti-inflammatory factors in finishing cattle.

Adult Ossabaw Pigs Prefer Fermented Sorghum Tea over Isocaloric Sweetened Water

Ossabaw pigs (n = 11; 5-gilts, 6-barrows; age 15.6 ± 0.62 SD months) were exposed to a three-choice preference maze to evaluate preference for fermented sorghum teas (FSTs). After conditioning, pigs were exposed, in four sessions, to choices of white FST, sumac FST, and roasted sumac-FST. Then, pigs were exposed, in three sessions, to choices of deionized H2O (-control; avoidance), isocaloric control (+control; deionized H2O and sucrose), and blended FST (3Tea) (equal portions: white, sumac, and roasted sumac). When tea type was evaluated, no clear preference behaviors for tea type were observed (p > 0.10). When the 3Tea and controls were evaluated, pigs consumed minimal control (p < 0.01;18.0 ± 2.21% SEM), and they consumed great but similar volumes of +control and 3Tea (96.6 and 99.0 ± 2.21% SEM, respectively). Likewise, head-in-bowl duration was the least for -control, but 3Tea was the greatest (p < 0.01; 5.6 and 31.9 ± 1.87% SEM, respectively). Head-in-bowl duration for +control was less than 3Tea (p < 0.01; 27.6 vs. 31.9 ± 1.87% SEM). Exploration duration was the greatest in the area with the -control (p < 0.01; 7.1 ± 1.45% SEM), but 3Tea and +control exploration were not different from each other (1.4 and 3.0 ± 1.45% SEM, respectively). Regardless of tea type, adult pigs show preference for FST, even over +control. Adult pigs likely prefer the complexity of flavors, rather than the sweetness alone.

Integrating 1G with 2G Bioethanol Production by Using Distillers’ Dried Grains with Solubles (DDGS) as the Feedstock for Lignocellulolytic Enzyme Production

First-generation (1G) bioethanol is one of the most used liquid biofuels in the transport industry. It is generated by using sugar- or starch-based feedstocks, while second-generation (2G) bioethanol is generated by using lignocellulosic feedstocks. Distillers’ dried grains with solubles (DDGS) is a byproduct of first-generation bioethanol production with a current annual production of 22.6 million tons in the USA. DDGS is rich in fiber and valuable nutrients contents, which can be used to produce lignocellulolytic enzymes such as cellulases and hemicellulases for 2G bioethanol production. However, DDGS needs a pretreatment method such as dilute acid, ammonia soaking, or steam hydrolysis to release monosaccharides and short-length oligosaccharides as fermentable sugars for use in microbial media. These fermentable sugars can then induce microbial growth and enzyme production compared to only glucose or xylose in the media. In addition, selection of one or more suitable microbial strains, which work best with the DDGS for enzyme production, is also needed. Media optimization and fermentation process optimization strategies can then be applied to find the optimum conditions for the production of cellulases and hemicellulases needed for 2G bioethanol production. Therefore, in this review, a summary of all such techniques is compiled with a special focus on recent findings obtained in previous pieces of research conducted by the authors and by others in the literature. Furthermore, a comparison of such techniques applied to other feedstocks and process improvement strategies is also provided. Overall, dilute acid pretreatment is proven to be better than other pretreatment methods, and fermentation optimization strategies can enhance enzyme production by considerable folds with a suitable feedstock such as DDGS. Future studies can be further enhanced by the technoeconomic viability of DDGS as the on-site enzyme feedstock for the manufacture of second-generation bioethanol (2G) in first-generation (1G) ethanol plants, thus bridging the two processes for the efficient production of bioethanol using corn or other starch-based lignocellulosic plants.